Alloyed steel suitable preferably for water hardening tools of high resistance to wear as well as shock



Patented Oct. 2, 1951 ALLOYED STEEL SUITABLE PREFERABLY FOR WATER HARDENING TOOLS OF HIGH RESISTANCE TO WEAR AS WELL AS SHOCK Helmuth Krainer and Karl Swoboda, Kapfenberg,

Austria, assignors to Gebr. Biihler & Co. Aktiengesellschaft, Vienna, Austria N Drawing. Application February 27, 1948, Se-

rial No. 11,874. In Germany October 31, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires October 31, 1961 3 Claims.

The invention relates to an alloy steel suitable preferably for water hardening tools of high resistance to wear as well as shock.

For such tools, especially for turning tools, for grooving or rifling tools and drawing dies, alloyed steels are used having a hardness of RC of at least 67, preferably 68 to 69 in the hardened state. The hardness should not decrease appreciably when tempered at a temperature of approx. 200 C., at least the hardness should not drop to less than 66 RC.

It is, however, not possible to choose a suitable alloyed steel merely according to the hardness obtainable. As the tools under consideration are causes brittleness of the tool.

purities, the components enumerated below:

1.0 to 2.0% carbon of less than 1%.

impurities 1.3 to 1.8% carbon steel of the following composition:

balance iron and the usual impurities. After quenching this steel in water from a temperature of 780-840 C. a RC hardness of 65-70 is obtained.

No decrease in hardness occurs on tempering at 100 C. Tempering at 200 C. does not decrease the RC hardness below 66.

Steel to be used according to the present invention proved in tests not only equal to a steel normally used for rifling tools with a tungsten content of 8% but was even superior in many cases.

The main advantage of the alloy used according to the present invention as compared with the steels normally known to be used for rifling used for extremely hard works, and as they are tools and having a high content of tungsten is its subjected to mechanical wear, the have to congreater toughness. Accordingly its application tain in their micro-structure carbides of very is not only valuable for rifling and grooving tools great hardness embedded in a hard matrix. As or drawing dies but generally for tools exposed is commonly known, steel of high carbon content to excessive wear and shock. is chosen and this steel is alloyed with the car- 0 What we claim is: bide forming elements chromium, vanadium and 1. Water hardening alloy tool steel having an tungsten, tungsten representing the main addi- RC hardness in the range of 65 to '70 and contion, the known alloys having a content of mostly taining more than 1% C, up to 1.5% Cr, up to 0.5% V 1.0 to 2.0% carbon and 4 to 8% W. The content of tungsten may be 0.8 to 2.5% vanadium reduced to 2%. The high content of tungsten 0.5 toless than 2% tungsten balance iron and impurities.

According to the present invention the content Water hardening alloy tool Steel as defined of tungsifm} 15 decreased the m in claim 1 containing additionally a small quanknown minimum by a var1at1on 1n the relative h t tity, less than 1% of chromium. gi f e q ferlrlmng 3. Water hardening alloy tool steel having an cor mg mven.1on.a Dyed S ee S are be RC hardness in the range of 65 to 70 and conused containing, besides iron and the usual 1mtaming 1.3 to 1.8% carbon 0.1 to 0.6% chromium 0.8 to 2.5% vanadium 1.0 to 1.75% vanadium 0.5 to less than 2% tungsten 1.0 to less than 2% tungsten The steels may also have a content of chromium balance iron and impurities The alloy to be used according to the present HELMUTH KRAINER invention is found to display its extremely fa- KARL SWOBODA vourable properties most reliably if the concentrations of the carbide forming elements are kept REFERENCES CITED within relatively close limits. Especially suitable The followin ref is the alloy containing besides iron and the usual file of this patgem: e ences are of record m the UNITED STATES PATENTS 0.1 to 0.6% chromium Number Name Date L6 t 115 vanadium 1,496,980 Armstrong June 10, 1924: 1.0 to less than 2% tungsten FOREIGN PATENTS In tests the best results were obtained with a Number Country t 180,112 Switzerland Dec. 16, 1935 1.6% carbon 0.3% chromium 1.4% vanadium 1.6% tungsten 

1. WATER HARDENING ALLOY TOOL STEEL HAVING AN RC HARDNESS IN THE RANGE OF 65 TO 70 AND CONTAINING 1.0 TO 2.0% CARBON 0.8 TO 2.5% VANADIUM 0.5 TO LESS THAN 2% TUNGSTEN BALANCE IRON AND IMPURITIES.
 2. WATER HARDENING ALLOY TOOL STEEL AS DEFINED IN CLAIM 1 CONTAINING ADDITIONALLY A SMALL QUANTITY, LESS THAN 1% OF CHROMIUM. 